The invention relates to a nominal value pick up for drive controls, preferably sew drive controls.
Drive controls in form of position drives for driving a speed shaft with a speed controllable drive motor which is provided with a control, which is coupled with the drive shaft, and pick ups for the actual speed, the nominal speed, the actual position and the nominal position of the operting shaft (U.S. Pat. Nos. 3,487,438, 3,532,953, 3,761,790, 4,011,490).
In the following the invention is explained in more detail in conjunction with a nominal value pick up for sew drive controls. However, the subject described nominal value pick up is also suitable for other types of drives, for example, for drives of tool machines, capacitor winding machines, and the like.
Recently, machine manufacturers more and more use post frames which support the sewing table. Thereby, the mounting of the drive and in particular the mounting of the pedal actuated by the operator and the mounting of the nominal value pick up which is built into the drive for the advance nominal speed and the nominal speed stopping presents difficulties. It is already known to provide a nominal value pick up which is removably mounted in the control box of the drive control and to use it as an external pick up in conjunction with additional parts, like sheet metal housing, additional cables, base plate and clamps. However, this requires cumbersome assembly operations.